Machine for bonding together a pair of thermoplastic coated panels

ABSTRACT

For binding in face-contacting relation a pair of box panels coated with thermoplastic material, the machine and method of this invention utilize transport means for moving the box and panels along a predetermined path, positioning and holding means for moving one of the panels into a position of spaced relationship to the other of said panels and for holding the panels in spaced relation for a brief period of time, nozzle means interposed between the panels for directing a blast of hot air in the direction of the panels and at an angle so as to scavenge atmospheric air whereby the thermoplastic coating on the panels is quickly heated. Thereafter the panels are quickly and firmly forced into face-contacting relation while still under the influence of the stream of hot air, the panels being held together until a bond is established therebetween.

United States Patent [72] Inventor Dale K. Scott Jonesboro, Ga.

[21] Appl. No. 845.382

[22] Filed July 28, I969 [45] Patented Aug. 10, 1971 {73] Assignee The Mead Corporation [54] MACHINE FOR BONDING TOGETHER A PAIR OF THERMOPLASTIC COATED PANELS Primary Examiner-Theron E. Condon Assistant Examiner- Robert L. Spruill At!0rneyWalter M. Rodgers ABSTRACT: For binding in face-contacting relation a pair of box panels coated with thermoplastic material, the machine and method of this invention utilize transport means for moving the box and panels along a predetermined path, positioning and holding means for moving one of the panels into a position of spaced relationship to the other of said panels and for holding the panels in spaced relation for a brief period of time, nozzle means interposed between the panels for directing a blast of hot air in the direction of the panels and at an angle so as to scavenge atmospheric air whereby the thermoplastic coating on the panels is quickly heated. Thereafter the panels are quickly and firmly forced into face-contacting relation while still under the influence of the stream of hot air, the panels being held together until a bond is established therebetween.

Patented Aug. 10, 1971 4 Sheets-Sheet 1 INVENTOR DALE K. SCOTT ATTORNEY Patented Aug. 10, 1971 E Q g g ll {3 i w :1 0J i x 33v Sheets-Sheet 2 INVENTOR DALE K. SCOTT ATTORNEY 4 SheetsSheet 5 Patented Aug. 10, 1971 ATTORNEY T m @E RT m 00 MC S V NK E L A D 3 W mm B Y Em C v 0 in m mm mm on m g m E I- =3 wo. m 0 4m 8 Wl l fi mm m on. 3 mm o z m m n v I E E E I l E @m win ow mm -m Patented Aug. 10, 1971 3,597,900

4 Sheets-Sheet 4 I'N'VENTOR DALE K. SCOTT ATTORNEY 'vmosphere.

-'relatively large quantity of heated air in the space between a pair of panels to be secured together. This procedure requires that a substantial quantity of air be used and results in a tendency to overheat the apparatus and to render the ambient temperature excessive due to the wastage of heat to at- According to this invention, a source of air under high pressure is heated and then supplied at high velocity at an angle to the panels to be bonded, a component of the jet blast being in' the same general direction'as the direction of movement of the folding box and of the panels to be bonded. Thus according to one feature of the invention a limited quantity of air is em ployed and excessive wastage of heat and the attendant increasein ambient temperature is avoided. Furthermore the fact that the heated air is directed in the general direction of movement of the folding box and the panels to be bonded ensures that the thermoplastic material will remain in a plastic condition at leastuntil pressure-applying means is employed topress and to hold the panels to be bonded in secure fixed relation to each other until a bond therebetween is established. According to one facet of the invention, an improved nozzle is employed which comprises an elongated tubular main body portion disposed at an angle to the path of movement of the box and panels to be bonded, the nozzle being disposed so as to preclude a disruptive collision with the panelsto be bonded, thus to avoid the attendant disruptive effects of such a collision.

For a better understanding of the invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings in which:

FIG.'I isa perspective view of certain essential components of a machine constructed according to this invention and I which seal the front panels of the carton;

FIG. 1A is a perspective view of a folding box constructed preferably of paperboard and which comprises a tray portion,

a cover portion, and three sealing flaps all of which are coated with thermoplastic material, and which are bonded to the sides and ends of the tray portion of the box according to this 1 I invention;

FIG.'1 B is a perspective view similar to FIG. 1A but showing the folding box in closed and sealed position;

FIG. 2 is a perspective view generally similar to FIG. I but showing the parts of the machine which seal the end panels of the carton;

' FIG.'3 is a side view of a machine constructed according to this invention;

FIG; 4 is a plan view of the arrangement depicted in FIG. 3; FIG. 5 is'an end view as seen from the right-hand end of the machine depicted in FIGS. 3 and 4;

F IG'. 6 is a schematic plan view of the right-hand portion of dthe machine as'shownin FIGS. 3, 4 and 5;

FIG. 7 is. a cross-sectional view taken along the line designated 7-7 inFIG. 6 and showing certain parts of the panel positioning and holding mechanism;

'FIG. 8 is a view-taken along the line designated 8-8 in FIG. 6 and is representative of the panels to be bonded and their relationship to the nozzle means and the panel holding means; FIG'. 9 is a side view partially in section of a nozzle con-' structed according to this invention; and

7 FIG. 10 --is a cross-sectional view taken along the line designated 1040 in FIG. 9.

The carton C" depicted in FIGS. IA and IB comprises a tray' portion generally designated by the numeral 1 in which a bottom'wall 2, a backwall 3, an end wall 4 and a front wall 5 are employed. In FIG. 1A theend wall opposite wall 4 is not observable. Of course all of the sidewalls are secured together at their ends and the cover portion generally designated by the numeral 6 comprisesa top panel 7 and a front panel 8 foldably joined to top panel 7 along fold line 9. Preferably a tear strip 10 is formed in front panel 8. End panel 11 is foldably joined to top panel 7 along fold line 12 and is provided with a removable tear strip 13. In similar fashion, end panel 14 is foldably joined to toppanel 7 along fold line 15 and is provided with a removably tear strip 16.

A machine constructed according to this invention effectively bonds front panel 8jof the cover portion 6 to front wall 5 of the tray portion 1 of the box. In addition, the machine and method of this invention effectively bond end panel l4'to sidewall 4 and end panel 11 to the end wall of the tray portion 1 of the box which is opposite to end panel 4. The bonding action is effected, for example, along the edge of end panel 8 which is remote from top wall 7 and which is designated as 8A. Thus when tear strip 10 is removed and when'the remaining tear strips such as 13 and 16 are removed the cover portion 6 may be opened.

When the folding box depicted in FIG. 1A is closed and sealed according to this invention the resultant closed'container appears as depicted in FIG. 1B.

In the specification and claims the panels to be bonded are referred to in some instances merely as panels of a folding box. Of course the panels to which reference is made constitute panels such as 5 and 8 forming the front portion of a container or panels such as 4 and 14 forming the end portion of the box. Likewise panel 11 and the associated end panel of the box are contemplated by the term panel.

In the drawings the numerals 17 and 18 denote directions of movement ofa folding box such as is depicted in FIGS. 1A and 13. During movement of the folding box in the direction indicated by arrow 17, the panel 8 is manipulated and then bonded to panel 5. Upon completion of this operation the carton changes its direction of movement but not its orientation and moves bodily at right angles to the direction indicated by the arrow 17 and thus moves in the direction indicated by the arrow I8. During this latter movement in the direction of arrow I8, the panels 11 and 14 are bonded to the end panels of the tray portion of the box.

As is best seen from FIGS. 3 and 4, the machine comprises an infeed conveyor 19 which is trained about rollers 20 and 21 one of which is a driven roller and both of which are generally supported by known bearing means onto the frame of the machine which in the drawings is schematically represented. The working reach of infeed conveyor 19 is supported by a plurality of idler rolls22.

.For receiving the boxes from the infeed conveyor 19 and for establishing a spaced relationship between succeeding boxes, an acceleration conveyor 23 isprovided and is movably mounted on rolls 24 and 25 supported by the machine frame.

Positive and controlled motion is imparted to the boxes by the transport conveyor 26 which preferably is in the form of endless chains on which pusher elements 27 are mounted. Chains 26 are mounted on sprockets 28 and 29 and are driven in synchronism with the remaining portions of the machine so that a pusher element such as 27 is movable behind a box and positively urges a particular box from left to right as viewed in FIG. 3 and in the direction of arrow 17.

For the purpose of gently engaging the top of panel 7 of a box and for swinging that panel from a vertical or open position downwardly into closed position, a pair of fixed guides 30 and 31 are mounted atop pedestals 32 and 33.

Front panel 8 is held at an angle to front wall panel 5 by "suitable guides such as the fixed guide 34 after having been folded downwardly by the movable positioning and holding element 35 rotatably mounted on shaft 36 affixed to the frame of the machine. While held in the position such as that depicted for example in FIG. I, an application of heat is made by means of nozzle 37. Following an application of heat, the carton continues its movement toward the right under the influence ofone of the pusher elements such as 27 until it is captured between a pair of pressure belts 38 and 39 which are provided with working reaches movable in the direction of movement of the carton. Belts 38 and 39 are provided along their inner surfaces with inwardly extending projections which cooperate with cogs which are rotatable about vertical axes and driven in synchronism with each other and with the other machine elements. The working reaches of the pressure belts 38 and 39 move at a greater velocity than the transport conveyor 26 in order to prevent a collision between pushers 27 and the carton end wall when the pusher swings downwardly toward the return reach of conveyor 26v During the period when the pressure belts 38 and 39 are holding the panels such as 8 into close face-contacting relationship to panel 5, the box is in effect being pressed and conveyed by the belts 38 and 39 according to one feature of the invention.

The entire length of the machine as described thus far is enclosed by a pair of oppositely disposed sideplates 40 and 41 as is apparent in FIG. 4. For the purpose of affording reinforcement for the machine and to serve as support for the cartons during certain portions of their travel through the machine, the transversely disposed rodlike elements 42 and 43 are provided. Thus while a carton is moved by chains 26, it slides on rails 42 and 43.

As is best shown in FIG. 1, a carton is disposed with its back panel 3 toward the left and with its end panel 4 in a leading relation to the remaining panels. Of course the front wall is disposed to the right and the panel 8 is to be secured to wall 5.

For the purpose of holding the top panel 7 downwardly in closed position, a pair of holding elements in the form ofdisks 44 and 35 are mounted on rotatable shafts 36 supported in cantilever fashion in a bearing generally designated by the numeral 47. Of course bearing 47 is adjustable from left to right by sliding action in the slot 48 formed in housing 49. Housing 49 is vertically adjustable in known manner by virtue of the rotatable wheel 50. Up and down and horizontal adjustment of disks 44 and 35 is necessary in order to adapt the machine to cartons of different sizes.

The action of disks 44 and 35 is simply to hold the cover 7 closed and to prevent frictional drag on the cover 7 from skewing the cover. These elements rotate in a counterclockwise direction and at a speed such that the peripheral velocity is greater than the velocity of movement of the cover and at the same speed as belts 38 and 39 and by this means the frictional drag of the guides which tends to skew cover 7 is overcome.

Since the front panel 8 is provided with a removable tear strip 10, it is desirable to provide positive downward folding of panel 8 so as to prevent inadvertent folding of the panel along the tear strip and so as to insure that the entire panel is folded downwardly along fold line 9. To this end, flange element 51 is affixed to the periphery ofdisk 35 and engages panel 8 to fold that panel downwardly as is obvious from FIG. 1. With panel 8 folded downwardly to the position indicated in FIG. 1, a blast of hot air is supplied through the apertures 52--55 which are located on both sides of the tip of nozzle 37. The nozzle 37 is provided with a main body portion in which a baffle element 56 is disposed. Baffle element 56 is provided with a plurality of apertures 57 and serves to agitate the air entering the nozzle at the entry end 58 so as to establish a uniform temperature of air within the base portion of the nozzle before it is discharged through the apertures 52-55 formed in the tip portion ofnozzle 37.

As is best seen in FIGS. 1,2 and 9, the body portion of nozzle 37 is inclined upwardly to the path of travel of the cartons but the apertures 52-55 formed in the top portion of the nozzle are in alignment with the path of movement of the panels to be bonded. Since the apertures 52-55 are aligned in the direction of movement of the articles, it is possible to apply heat directly to that portion of panel 8 which is identified as 8A and not to the remaining portions thereof. Similarly only the lower portion 5A of panel 5 is effectively heated.

Since the nozzle 37 is disposed in general alignment with the direction of movement of the carton having panels to be bonded and since the sides 37A and 37B of the tip of the nozzle converge toward the end as best seen in FIG. 6, the blast of air from the apertures 5255 on each side of the nozzle is generally outwardly and forwardly so that a component of the blast is in the direction of movement of the panels to be bonded such as 5 and 8 as indicated by arrow 17. Due to this orientation of the blast and due to the relatively high velocity thereof, atmospheric air is efficiently and effectively scavaged away from the surfaces of panels 8 and 5 which are to be bonded. This very efficient scavaging action allows heating of the thermoplastic material on panels 8 and 5 which is quick and efficient without dissipating large quantities of heat into the atmosphere. Furthermore, since the pressure rolls 38 and 39 are disposed immediately downstream from the tip of nozzle 37 and since a component of the hot blast of air is directed in a downstream direction, the thermoplastic material is under the influence of the hot air until the panels are forced together in flat face-contacting relationship by the pressure belts 38 and 39. Thus the temperature of the air is not high enough nor is the jet blast effect of the hot air sufficiently forceful to dislodge the thermoplastic material from the panels to be bonded. Once the panel 8 is forced into contact with panel 5 by belt 38, the entire carton is transported from left to right in the direction of arrow 17 by both belts 38 and 39, it being apparent that the working reach of belt 39 is in engagement with back panel 1 of the tray portion of the carton.

In order to apply appropriate coding indicia to the cartons a known rotatable coding wheel 59 is disposed to engage and imprint suitable indicia on the panel 8 before that panel is bonded to panel 5. Coding device 59 forms no part of the present invention and is simply disclosed for the sake of completeness.

In the interest of conserving heat and of obtaining an efficient bond, it is vital that the panels such as 8 and 5 be quickly and efficiently heated only in the areas to be bonded and thereafter secured together in an immobile relationship by the pressure belts 38 and 39 until the bond in suitably formed.

. After panel 8 is secured to panel 5 it is then necessary to bond panels 11 and 14 to the end panels of the carrier. This operation is accomplished by mechanism identical to that already described and which is shown in FIGS. 2-6 inclusive. The mechanism simply duplicates the nozzle and associated structure previously described on each side of the path of travel. For example in FIG. 4 nozzles 37D and 37E and associated structure heat the appropriate panels such as 11 and 14 and their associated end panels and thereafter pressure is applied by pressure belts 38A and 39A. Motion is imparted to the carton by conveyor chain 26A along which pusher elements 27A are mounted and which impart movement from right to left as shown in FIG. 5 and as indicated by the arrow 18.

For the purpose of providing lateral adjustment for the fixed guide 61, adjustable guide plate 61A is employed and functions in known manner and in a similar fashion, guide 60 is adjustable laterally by the rotatable adjustment wheel 60A and parts associated therewith.

In order to aid belts such as 38 and 39 in applying firm and uniform pressure to the panels to be bonded a backup plate is provided adjacent the inner projections of the belts and along the working reach of such belt. One such plate is designated at 38B in FIG. 2.

The embodiments of the invention in which I claim an exclusive property or privilege are defined as follows:

Iclaim:

l. A machine for securing a thermoplastic coated panel of a folding box to another panel thereof, said machine comprising transport means for moving the box along a predetermined path, positioning and holding means engageable with one of said panels for moving such panel into a position of angular disposition and close proximity to the other panel, nozzle means fixed in position along said predetermined path and arranged so that said panels pass on opposite sides of said nozzle means with said nozzle means interposed therebetween, means for supplying heated fluid through said nozzle means and onto at least one of the opposed angularly disposed surfaces of said panels, and pressure-applying conveyor means disposed immediately adjacent and downstream of said nozzle means and movable in synchronism with said transport means for engaging and pressing one of said panels into firm and fixed relation relative to the other of said panels and for holding the panels in pressed and fixed relation to each other at least until the thermoplastic coating is afforded sufficient time to bond said panels together, said nozzle means comprising an elongated tubular element having a main body portion extending upwardly in the general direction of movement of the box and disposed in a vertical plane and at an angle to said predetermined path and positioned in the general region of divergence of said panels and said nozzle means including a tip portion having discharge apertures therein on opposite sides thereof and wherein said apertures are aligned with each other along a line which is angularly disposed relative to said main body portion and generally parallel with said predetermined path.

2. A machine according to claim 1 wherein the vertical sides of the tip of the nozzle converge toward the end of the nozzle and in the direction of movement of the box so as to direct a component of the blast in the direction of movement of the panels to be bonded.

3. A machine according to claim 1 wherein said positioning and holding means comprises a rotatable element having a peripheral velocity in the direction of movement of said transport means which is somewhat greater than the velocity of movement thereof along said predetermined path. 

2. A machine according to claim 1 wherein the vertical sides of the tip of the nozzle converge toward the end of the nozzle and in the direction of movement of the box so as to direct a component of the blast in the direction of movement of the panels to be bonded.
 3. A machine according to claim 1 wherein said positioning and holding means comprises a rotatable element having a peripheral velocity in the direction of movement of said transport means which is somewhat greater than the velocity of movement thereof along said predetermined path. 